The useful line under the Meta Description section, showing how many characters are left, has stopped displaying for me!

It now says:

The meta description will be limited to 139 chars (because of date display), chars left.

The equivalent line under the Title section, is working intermittently. When you load the edit screen, even if a title exists, it's blank. But if you amend the title, the character count appears again, and updates as you type, as it should do.